I was based in Spain for a while with FR and the major problem I saw with the jumpseating is it was not monitored for rest by the company or Ryanair (to the best of my knowledge)
Guys were jumpseating in on up to 3 flights due no directs for some then having at best 4 hours sleep then heading in to do a 2 or 4 sector day.
Then after 5 days flying earlys they would wait around or rush around to get the afternoon flight('s) home again. And do it all again the next week with the reverse onto late's.
This would lead to some very very tired looking guys in the bar/restaurant on an evening and not the sort of guy I would want sat at the pointy end when I was going home.
Of course this is just pure guess work and speculation and not to be taken as fact for obvious reasons.